覆盖方式对土壤水分和硝态氮分布积累特征的影响

Effect of the Covering Methods on Soil Moisture and Nitrate Nitrogen Distribution and Accumulation Characteristics

在北方旱农区寿阳县,对不同覆盖耕作措施条件下土壤水分和硝态氮运移状况进行了研究。结果表明,较露地种植而言,地膜、秸秆二元覆盖、宽膜覆盖和窄膜覆盖的0～40 cm土层各生育期土壤含水量高于播种期,40～120 cm土壤含水量变化较为剧烈,而120～200 cm土层土壤含水量变化相对平缓,其中,保墒效果表现为二元覆盖〉宽膜覆盖〉窄膜覆盖,说明二元覆盖能够更好地蓄水保墒、减少径流和蒸发、补充土壤水分;抽雄期和灌浆期虽进入雨季,但土壤储水量仍处于下降趋势,作物生长耗水是土壤储水量下降的主要原因;从各处理土壤硝态氮剖面分布看,地膜覆盖能有效地促进玉米对土壤硝态氮的吸收,窄膜覆盖、宽膜覆盖和二元覆盖累积的硝态氮主要分布在0～100 cm土层。

The paper analyzed the soil moisture and nitrate nitrogen dynamic under four plastic mulching patterns, i.e. not mulching, normal plastic film mulch ＋straw mulch between rows, wide plastic film and narrow plastic film, in Northern arid region of Shouyang county. The results showed that, compared with bare land cultivation, soil moisture storage of 0- 40 cm soil layer of three mulching patterns in different growth period were higher than the sowing time, 40- 120 cm soil moisture storage changed more violent,and the changes of 120- 200 cm of soil moisture storage was relatively flat. In keep moisture effect, it was double mulching filmwide plastic filmnarrow plastic film. Double mulching film was best in reducing runoff and soil moisture evaporation. Tasseling stage and filling stage entered the rainy season, but the soil water storage was still in a downward trend for the growth of crop. From the process of nitrate nitrogen in soil profile distribution, plastic film mulching could effectively promote the absorption of nitrate nitrogen in soil, which mainly distributed in 0- 100 cm soil layer.